Communication system, communication device and communication terminal device

ABSTRACT

Provided is a technology which pertains to wireless LAN communication systems and with which it is possible to achieve convenience in that a terminal of a user who is external to an organization can temporarily use the system and to ensure security in such a case. The present communication system comprises: a first terminal which is used by a user internal to an organization; a second terminal which is used by a user external to the organization; and a communication device which has a display function and a wireless LAN access point function inside the organization. The first terminal connects to the communication device via a wireless LAN. The second terminal connects, under permission from the first terminal, to the communication device via the wireless LAN. The second terminal uses the display function of the communication device through the connection via the wireless LAN. The first terminal and the communication device confirm whether the permission is to be continued or terminated. In response to a termination of the permission, the communication device terminates the connection with the second terminal via the wireless LAN to make the second terminal unable to use the display function.

TECHNICAL FIELD

The present invention relates to communication and informationprocessing technologies. Furthermore, the present invention relates tothe technologies of a wireless LAN, a projector, and the like.

BACKGROUND ART

Conventionally, there has been, as an example of a wireless LANcommunication system in an organization, such as a company, acommunication system in which a terminal of a user who is internal to acompany wirelessly connects to a communication device which has awireless LAN access point function. The terminal of the user who isinternal to the company wirelessly connects to the communication devicewhich has the access point function and uses a predetermined function ofthe communication device.

An example of the conventional technologies which relate to a wirelessLAN communication system is described in Japanese Unexamined PatentApplication Publication No. 2005-51314A (Patent Document 1). PatentDocument 1 describes that, in a wireless LAN system where a clientterminal of a user and a communication device, which is a wireless LANaccess point, wirelessly connect to each other, a time period in whichthe client terminal is allowed to connect to the access point is set,and security is ensured by a control based on this time restriction.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2005-51314

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The above-described wireless LAN communication system is assumed toencounter not only a situation where a terminal of a user who isinternal to an organization connects to and uses a communication devicewhich has an access point function, but also a situation where aterminal of a user who is external to the organization connects to anduses the same communication device. For example, in a meeting at acompany or the like, a user who is internal to the company allows aninvited user who is external to the company to temporarily use awireless LAN communication system inside the company. Specifically, theterminal of the user who is external to the company temporarily connectsto the communication device which has an access point function and usesa predetermined function.

Such a wireless LAN communication system by which the functionscorresponding to the above-described situations of use are achieved isadvantageous in terms of convenience. However, such a system has apossibility that a terminal of a user who is external to an organizationcan independently use the wireless LAN communication system inside theorganization after a temporary use. In other words, the above-describedwireless LAN communication system has a problem in terms of a balancebetween convenience and security.

An object of the present invention is to provide a technology pertainingto a wireless LAN communication system, a communication device in thesystem, and the like, which can achieve convenience for a terminal of auser who is external to an organization to temporarily use the systemand ensure security in such a case.

Means for Solving the Problems

A representative embodiment of the present invention is a communicationsystem and the like and is characterized by including the followingconfiguration.

A communication system of an embodiment includes: a first communicationterminal device having a wireless LAN connection function, a secondcommunication terminal device having a wireless LAN connection function,and a communication device having a wireless LAN access point functionand a display function. The first communication terminal device connectsto the communication device via a wireless LAN. The second communicationterminal device connects, under permission from the first communicationterminal device, to the communication device via the wireless LAN anduses the display function of the communication device through theconnection. The first communication terminal device and thecommunication device communicate with each other to confirm whether thepermission for the second communication terminal device to connect toand use the communication device is to be continued or terminated. Inresponse to a termination of the permission, the communication deviceterminates the connection with the second communication terminal devicevia the wireless LAN to make the second communication terminal deviceunable to use the display function.

Effects of the Invention

The representative embodiment of the present invention, pertaining to awireless LAN communication system, a communication device in the system,and the like, can achieve convenience for a terminal of a user who isexternal to an organization to temporarily use the system and ensuresecurity in such a case.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a communicationsystem of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an overview of use in the communicationsystem of the embodiment.

FIG. 3 is a diagram illustrating a configuration of a projector which isa communication device of the embodiment.

FIG. 4 is a diagram illustrating a configuration of a first terminalwhich is a communication terminal device of the embodiment.

FIG. 5 is a diagram illustrating a configuration and process sequence ofa communication system of Embodiment 1 of the present invention.

FIG. 6 is a diagram illustrating a configuration and process sequence ofa communication system of a first modified example of Embodiment 1.

FIG. 7 is a diagram illustrating a configuration of a communicationsystem of a second modified example of Embodiment 1.

FIG. 8 is a diagram illustrating a configuration and process sequence ofa communication system of Embodiment 2 of the present invention.

FIG. 9 is a diagram illustrating a configuration and process sequence ofa communication system of a modified example of Embodiment 2.

FIG. 10 is a diagram illustrating a configuration and process sequenceof a communication system of Embodiment 3 of the present invention.

FIG. 11 is a diagram illustrating a configuration and process sequenceof a communication system of Embodiment 4 of the present invention.

FIG. 12 is a diagram illustrating a configuration and process sequenceof a communication system of Embodiment 5 of the present invention.

FIG. 13 is a diagram illustrating a configuration and process sequenceof a communication system of Embodiment 6 of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below in detailon the basis of the drawings. Note that the same reference signs areprincipally assigned to the same elements throughout the drawings forillustrating the embodiments, and repetitive descriptions thereof areomitted.

Communication systems of the embodiments provide the function oftemporarily connecting, under permission from a terminal of a user whois internal to a company, a terminal of a user who is external to thecompany, to a projector which has a wireless LAN access point functionand enabling the terminal of the user who is external to the company touse a display function of the projector.

First, a configuration practically common to the embodiments isdescribed with reference to FIG. 1 to FIG. 4, followed bycharacteristics of the individual embodiments described in order.

[Communication System]

FIG. 1 illustrates a configuration of a communication system of anembodiment. The communication system in FIG. 1 is a system including awireless LAN 4. The communication system further includes a projector 3,which is a communication device, a terminal 1, which is a firstcommunication terminal device, and a terminal 2, which is a secondcommunication terminal device. The projector 3 is connected to theterminal 1 and terminal 2 via the wireless LAN 4. The projector 3 isconnected to a communication network 5. A connection 41 via the wirelessLAN is established between the projector 3 and the terminal 1. Aconnection 42 via the wireless LAN is established between the projector3 and the terminal 2. A connection 43 using short range communication isestablished between the terminal 1 and the terminal 2.

The wireless LAN 4 is a wireless LAN compliant with a predeterminedcommunication standard. Although Wi-Fi is applied as the communicationstandard of the wireless LAN 4 in the present embodiment, anycommunication standard is applicable without being limited to Wi-Fi.Wi-Fi, i.e., wireless fidelity, is a term indicating thatinterconnections between devices in accordance with the internationalstandard, IEEE 802.11, are approved. The wireless LAN 4 is illustratedwith a hotspot thereof. The hotspot is a space in which wirelessconnections are possible around the projector 3, which is acommunication device serving as an access point in the wireless LAN 4.

The wireless LAN 4 is a wireless LAN established inside a company A,which is an organization, and the projector 3 and the terminal 1 of auser A, which are elements constituting the wireless LAN 4, are underthe management of the company A. The terminal 2 of a user B is outsidethe management of the company A. FIG. 1 illustrates a case where theterminal 1 of the user A who is internal to the company A and theterminal 2 of the user B of a company B outside the company A arelocated within the hotspot of the wireless LAN 4.

The communication network 5 indicates a wired intra-company LAN in thecompany A, which is an organization, the Internet which is an externalnetwork to which connections are established via the intra-company LAN,and the like.

The projector 3 is a device serving both as a projection type displaydevice and a communication device serving as an access point of thewireless LAN 4. The projector 3 includes a display function 31, awireless LAN access point function 32, a router function 33, and thelike.

The display function 31 is the function of projecting and displaying amoving image or a still image on a screen for the projector 3. Thewireless LAN access point function 32 is the function of establishing awireless connection to a communication terminal device via the wirelessLAN 4 compliant with Wi-Fi standards. The router function 33 is thefunction of performing routing for a connection to the communicationnetwork 5 and includes layer-2 and layer-3 protocol processingfunctions.

Note that the projector 3 includes a short range communication function34 in, for example, Embodiment 4 to be described later. The short rangecommunication function 34 is the function of performing short rangecommunication with a communication terminal device.

The user A, such as an employee who is internal to the company A,possesses and uses the terminal 1. Note that not only the user A butalso another user such as another employee of the company A cansimilarly establish a connection to the wireless LAN 4 with acommunication terminal device. The user B, such as an employee of thecompany B outside the company A, possesses and uses the terminal 2. Anyof various kinds of communication terminal devices including asmartphone, a tablet terminal, a laptop computer, and the like can beused as each of the terminal 1 and the terminal 2.

The terminal 1 includes a wireless LAN connection function 11 and ashort range communication function 12. Similarly, the terminal 2includes a wireless LAN connection function 21 and a short rangecommunication function 22. The wireless LAN connection function 11 isthe function of establishing the Wi-Fi connection 41 via the wirelessLAN 4 to the access point function 32 of the projector 3 and performingwireless communication, such as data communication, with the connection41 established. Similarly, the wireless-LAN connection function 21 isthe function of establishing the Wi-Fi connection 42 to the access pointfunction 32 of the projector 3.

The connection 43 using short range communication is possible betweenthe short range communication function 12 of the terminal 1 and theshort range communication function 22 of the terminal 2. In the presentembodiment, NFC, i.e., near field communication, which has a narrowdefinition of short range communication, is applied as the short rangecommunication. However, any type of short range communication isapplicable without being limited to NFC. NFC is also called non-contactcommunication, and examples of the standards of NFC are Felica(registered trademark), ISO/IEC 14443, and ISO/IEC 18092. The shortrange communication may be, for example, Bluetooth (registeredtrademark) or may be any communication using infrared rays or audioother than the above types of communication using radio waves.

The terminal 1 of the user A can use the display function 31 with theconnection 41 to the projector 3 established. Specifically, the user Acan transmit data, such as material retained in the terminal 1, to theprojector 3 through the connection 41 to cause the display function 31of the projector 3 to display the data on the screen. In the presentembodiment, the terminal 2 of the extra-company user B can establish theconnection 42 to the projector 3 under permission from the terminal 1 ofthe intra-company user A to temporarily use the display function 31 ofthe projector 3. Specifically, the user B can transmit data, such asmaterial retained in the terminal 2, to the projector 3 through theconnection 42 to cause the display function 31 of the projector 3 todisplay the data on the screen.

Moreover, the terminal 1 of the user A can connect to the communicationnetwork 5 by using the router function 33 with the connection 41 to theprojector 3 established. Specifically, the user A can access, forexample, a server on an intra-company LAN or a server on the Internetwith the terminal 1 to, for example, download and upload data from andto the server.

In the present embodiment, the terminal 2 of the extra-company user Bcan establish the connection 42 to the projector 3 under permission fromthe terminal 1 of the intra-company user A to connect to thecommunication network 5 through the temporary use of the router function33 of the projector 3. Specifically, the user B can access, for example,a server on the Internet with the terminal 2 to, for example, downloadand upload data from and to the server. Note that, from a securityviewpoint, a fire wall server or the like is usually set up to preventthe terminal 2 of the extra-company user B from connecting to thecommunication network 5 such as an intra-company LAN.

In the present embodiment, the projector 3, which is a type displaydevice, serves as a communication device constituting the wireless LAN4, and the display function 31 and the router function 33 serve as thefunctions which are temporarily used by the terminal 2 of theextra-company user B. Without being limited to the above, thecommunication device constituting the wireless LAN 4 may be a monitordevice or a television device, which is a non-projection type displaydevice, or may be a device providing a function other than the displayfunction 31, in other embodiments. When it is assumed that the projector3 is replaced with a different device and the display function 31 isreplaced with a different function, the communication system of thepresent embodiment includes the different function of the differentdevice as a predetermined function for permission to be given. Thedisplay function 31 may be a display function of displaying a movingimage or a still image on a display screen formed of a liquid crystalpanel. The different function may be the function of receiving abroadcast in the form of radio waves and displaying the broadcast.

Other embodiments may have a configuration in which the router function13 of the projector 3 is omitted, in other words, a configuration inwhich the projector 3 and the communication network 5 do not connect toeach other. The use of the router function 33 by the terminal 2 of theuser B may be allowed under permission from the terminal 1 of the user Aor may be forbidden due to non-permission from the terminal 1 inaccordance with the setting function of the present embodiment.

In the above configuration, the connection 41 between the terminal 1 andthe projector 3 is a wireless connection as an example. However, theconnection 41 may be a wired connection.

[Overview of Use]

An overview of use including situations of use regarding thecommunication system of the embodiment is described with reference toFIG. 2. FIG. 2 illustrates an overview of use in the communicationsystem of the embodiment along a time axis. As an example of situationsof use, the projector 3, which is an access point of the wireless LAN 4as in FIG. 1, is placed in a building of the company A. In a hotspot ofthe wireless LAN 4 in the building of the company A where the projector3 is placed, the user A of the company A and the invited user B of thecompany B have a meeting.

First, assume that the user A wirelessly connects his/her own terminal 1to the projector 3 to use the display function 31 and the like of theprojector 3, as indicated by 211 to 213. 211 indicates the process ofestablishing the connection 41 via the wireless LAN 4 by using theconnection function 11 of the terminal 1 of the user A and the accesspoint function 32 of the projector 3. 212 indicates the process and thetime of using the display function 31 of the projector 3 from theterminal 1 with the connection 41 established. 213 indicates the processof terminating the connection 41 via the wireless LAN 4 by using theconnection function 11 of the terminal 1 of the user A and the accesspoint function 32 of the projector 3.

201 indicates permission from the terminal 1 of the user A for theterminal 2 of the user B to connect to and use the projector 3. The userA gives the permission indicated by 201 under the condition that theterminal 1 of the user A and the terminal 2 of the user B are locatedclose to each other and the user A knows the existence of the user B ata time, for example, at the start of the meeting or during the processindicated by 211. Operations and processes for the permission aredescribed in detail in each embodiment.

The user B wirelessly connects the terminal 2 to the projector 3 underthe permission indicated by 201 to use the display function 31 and thelike of the projector 3 as indicated by 221 to 223. 221 indicates theprocess of establishing the connection 42 via the wireless LAN 4 byusing the connection function 21 of the terminal 2 of the user B and theaccess point function 32 of the projector 3. 222 indicates the processand the time of using the display function 31 of the projector 3 fromthe terminal 2 with the connection 42 established. 223 indicates theprocess of terminating the connection 42 via the wireless LAN 4 by usingthe connection function 21 of the terminal 2 of the user B and theaccess point function 32 of the projector 3.

202 indicates termination of the permission from the terminal 1 of theuser A for the terminal 2 of the user B to connect to and use theprojector 3. The user A terminates the permission as indicated by 202under the condition that the connection 41 between the terminal 1 of theuser A and the projector 3 is terminated at a time, for example, at theend of the meeting or during the process indicated by 213. Thetermination of the permission terminates the connection 42 between theterminal 2 of the user B and the projector 3 as indicated by 223.Thereafter, the terminal 2 of the user B does not have permission and ishence unable to independently connect to and use the projector 3 as in221 and 222.

Note that FIG. 2 illustrates an example in which the terminal 1 of theuser A first uses the display function 31 of the projector 3 and theterminal 2 of the user B subsequently uses the display function 31 ofthe projector 3 in parallel with the use by the terminal 1 of the user Ain terms of time. Without being limited to the above configuration, theprocesses indicated by 211 and 212 may first be carried out andterminated by the terminal 1 of the user A, and thereafter the processesindicated by 221 to 223 may be carried out by the terminal 2 of the userB, for example. In this case, the terminal 1 of the user A has stoppedusing the display function 31 while continuing the connection 41 to theprojector 3.

Moreover, in FIG. 2, termination of permission 202 is performed underthe condition that the connection 41 between the terminal 1 of the userA and the projector 3 has been terminated. However, the termination ofpermission 202 may be performed through an operation by the user A orthe like to terminate the connection 42 between the terminal 2 and theprojector 3, with the connection 41 established.

[Communication Device]

FIG. 3 illustrates a configuration of the projector 3, which is acommunication device of the embodiment. The projector 3 in FIG. 3 is aprojection type video display device, such as a liquid crystalprojector. The projector 3 may be a small portable device or astationary device. The projector 3 corresponds to a stand-aloneprojector which has a control function therein for display control inthis embodiment. However, the projector 3 may be a system type projectorconfigured to connect to an external device which has a control functionthereof. With the latter type, the projector 3 is connected to anexternal device, such as a PC, receives a command or the like from theexternal device, and then performs display control in accordance withthe command or the like.

The projector 3 has a configuration in which a CPU 301, a RAM 302, a ROM303, a secondary storage device 304, an input/output interface 305, aninput device 306, an output device 307, a power supply 308, a videoprocessor 311, an optical system and drive system 312, a radio part 320,a wired LAN interface 330, an NFC communication part 340, and the likeare connected to each other via a bus.

The CPU 301 is a controller which performs processes for controlling theentire projector 3 including control of the display function 31, theaccess point function 32, and the like. The RAM 302 is a memory whichstores processing data and the like. The ROM 303 is a memory whichstores an application 35, which is a control program, settinginformation 36, and the like. The CPU 301 loads a control program fromthe ROM 303 into the RAM 302 and executes the program to carry out eachprocess.

The application 35 carries out a process for implementing functionsunique to the projector 3 of the present embodiment. The CPU 301 carriesout software processing of the application 35. In the settinginformation 36, data and information for implementing the functionsunique to the projector 3 of the present embodiment are set. Theapplication 35 and the setting information 36 may be stored in thesecondary storage device 304, a memory in the radio part 320, or thelike.

The secondary storage device 304 is a memory card, a disk, or the likeand stores video data and the like. The input/output interface 305connects to an input device 306 and an output device 307 of variouskinds and carries out input/output interface processes. The power supply308 supplies power to each of the elements of the projector 3. The powersupply 308 turns the power on or off in response to a user operation.

The projector 3 causes the display function 31 to convert data to bedisplayed into a video signal for projection and to project and displaya video on a screen 313 on the basis of the video signal. The displayfunction 31 includes, as main components, the video processor 311, andthe optical system and drive system 312 in addition to the controller301. The video processor 311 carries out a process for selecting andreading data to be displayed from the radio part 320 or the like andconverting the data into a video signal for projection onto the screen313, and the like.

The optical system and drive system 312 include, for example, variousoptical components including a lamp, a liquid crystal panel device, aprojection lens, a reflection mirror, and the like, and the drivecircuits thereof. The optical system is driven on the basis of the videosignal for projection. With this configuration, the optical system anddrive system 312 emit light corresponding to the video signal andproject the light through the projection lens onto the screen 313 todisplay the video.

The wireless LAN access point function 32 allows the projector 3 as anaccess point to directly connect to the communication terminal device ina wireless transmission system. The projector 3 includes the radio part320 as a component of the access point function 32. The radio part 320is a wireless LAN interface compliant with the Wi-Fi standards and is amodule composed of an LSI or the like, which carries out radio signaltransmission/reception processes and the like. The radio part 320 canreceive data signals included in radio signals from the terminal 1 orthe terminal 2 in the Wi-Fi system.

The radio part 320 includes an antenna 321, an RF chip 322, an AP chip323, a memory 324, and the like. The RF chip 322 carries out receptionand transmission processes including modulation and demodulation of aradio signal, via the antenna 321. The AP chip 323 carries out aspecific application process on a radio signal and data, and reads andwrites information from and to the memory 324. The radio part 320 storesthe received radio signal data in a buffer memory. The buffer memory maybe a memory in the AP chip 323 or may be a memory 324 outside the APchip 323. The CPU 301, which is a controller, and the video processor311 can select and read the radio signal data from the buffer memory inthe radio part 320.

The memory 324 stores connection information, such as an SSID andpassword, as information necessary for wireless connection in the Wi-Fisystem, for example. The password is indicated by PW.

For a wireless connection between a communication terminal device andthe projector 3 by using the access point function 32, the radio part320 receives connection information including an SSID and password fromthe communication terminal device. The radio part 320 establishes theconnection to the communication terminal device when the receivedconnection information matches connection information including an SSIDand password held in the memory 324 and does not establish theconnection when the received connection information does not match anyconnection information held in the memory 324, for example.

The projector 3 includes the wired LAN interface 330 as a component ofthe router function 33. The wired LAN interface 330 includes a port anda processor, and carries out layer-2 and layer-3 protocol processing andthe like, connects to the communication network 5, transmits data to adevice in the communication network 5, and receives data from a devicein the communication network 5.

The projector 3 includes the NFC communication part 340 as a componentin an embodiment including the short range communication function 34.The NFC communication part 340 is a communication interface compliantwith NFC and includes an antenna coil 341, an RF circuit 342, aprocessing circuit 343, a memory 344, and the like. The RF circuit 342transmits and receives a signal of short range communication in NFC, viathe antenna coil 341. The processing circuit 343 carries out a specificprocess on a signal to be transmitted or a received signal. Theprocessing circuit 343 reads and writes data and information from and toa memory in the processing circuit 343 or the memory 344 outside theprocessing circuit 343.

The projector 3 may include an operation panel and/or remote controller(not illustrated) as a user interface. The operation panel and/or remotecontroller is provided with various buttons and/or a display. Thedisplay displays information. A user can turn the power on and off, givean instruction for a display operation, and make settings of functions,and the like, by the use of the buttons of the operation panel and/orremote controller.

The projector 3 may provide a setting function (not illustrated)provided on the basis of a process executed by the CPU 301 or the like.The setting function displays a setting screen on the screen 313, thedisplay of the operation panel, or the like. While viewing the settingscreen, the user can, for example, input an instruction signal to theprojector 3 to make settings of functions of the projector 3.

In a case where the projector 3 performs display by using the displayfunction 31 with its connections to multiple communication terminaldevices established, the projector 3 may also display display data onthe screen 313 while switching to display data from a communicationterminal device selected in response to a user operation. Alternatively,the projector 3 may display pieces of display data from multiplecommunication terminal devices on the screen 313 in parallel and displaya selected piece of display data in an enlarged manner, for example.

Another embodiment has a configuration in which a communication terminaldevice performs control of the display operation and makes setting ofthe display operation for the projector 3. Specifically, the terminal 1may be used as a device which has a function corresponding to the remotecontroller of the projector 3. For example, the terminal 1 transmits asignal including a command for control or setting of the displayoperation and the like, to the projector 3 with the connection 41established. The projector 3, for example, controls the displayoperation by the display function 31 in accordance with a receivedsignal including a command or the like. The display operation includes,for example, starting or stopping of a video.

[Communication Terminal Device]

FIG. 4 is a diagram illustrating a configuration of the terminal 1,which is a communication terminal device of the embodiment. Note that,although the configuration of the terminal 2 is basically the same asthe configuration of the terminal 1, the terminal 1 and the terminal 2include different components depending on the difference in role in thecommunication system of the present embodiment. For example, as in FIG.5 to be described later, the terminal 1 includes a dedicated application15, but the terminal 2 does not need to include the dedicatedapplication 15.

The terminal 1 has a configuration in which a CPU 401, a RAM 402, a ROM403, a secondary storage device 404, an input/output interface 405, aninput device 406, an output device 407, a power supply 408, a radio part410, an NFC communication part 420, a telephone network communicationpart 430, a touch panel 440, a sensor 450, and the like are connected toeach other via a bus.

The CPU 401 is a controller which performs processes for controlling theentire terminal 1 including control of the connection function 11, theshort range communication function 12, and the like. The RAM 402 is amemory which stores processing data and the like. The ROM 403 is amemory which stores the application 15, which is a control program,setting information 16, and the like. The CPU 401 loads the controlprogram from the ROM 403 into the RAM 402 and executes the program tocarry out each process of the functions.

The application 15 carries out a process for implementing functionsunique to the terminal 1 of the present embodiment. The CPU 401 carriesout software processing of the application 15. In the settinginformation 16, data and information for implementing the functionsunique to the terminal 1 of the present embodiment are set. The settinginformation 16 may be stored in the secondary storage device 404, amemory in the wireless LAN communication part 410, or the like.

The secondary storage device 104 is, for example, a memory card or thelike. The input/output interface 405 connects to an input device 406 andan output device 407 of various kinds and carries out input/outputinterface processes. The power supply 408 supplies power to each of theelements of the terminal 1. The power supply 408 turns power on or offin response to a user operation.

The terminal 1 includes the radio part 410 as a component of theconnection function 11. The radio part 410 is a wireless LAN interfacecompliant with the Wi-Fi standards and is a module composed of an LSI orthe like, which carries out radio signal transmission/receptionprocesses and the like. The radio part 410 can receive a data signalincluded in a radio signal from the access point function 32 of theprojector 3 in the Wi-Fi system.

The radio part 410 includes an antenna 411, an RF chip 412, an AP chip413, a memory 414, and the like. The RF chip 412 carries out receptionand transmission including modulation and demodulation of a radiosignal, via the antenna 411. The AP chip 413 carries out a specificapplication process on a radio signal and data, and reads and writesinformation from and to the memory 414. The radio part 410 stores thereceived radio signal data in a buffer memory. The buffer memory may bea memory in the AP chip 413 or may be a memory 414 outside the AP chip413. The CPU 401, which is a controller, and the like can select andread the radio signal data from the buffer memory in the radio part 410.

The memory 414 stores information, such as an SSID and password, asinformation necessary for wireless connection in the Wi-Fi system, forexample.

To establish the connection 41 to the projector 3 by using theconnection function 11, the terminal 1 reads connection informationincluding an SSID and password held in the memory 414 and transmits theconnection information to the projector 3, through the radio part 410.

The terminal 1 includes the NFC communication part 420 as a component ofthe short range communication function 12. The NFC communication part420 is a communication interface compliant with NFC and includes anantenna coil 421, an RF circuit 422, a processing circuit 423, a memory424, and the like. The RF circuit 422 transmits and receives a signal ofshort range communication in NFC, via the antenna coil 421. Theprocessing circuit 423 carries out a specific process on a signal to betransmitted or a received signal. The processing circuit 423 reads andwrites data and information from and to a memory in the processingcircuit 423 or the memory 424 outside the processing circuit 423.

With NFC, non-contact data communication can be performed within acommunication distance of approximately 10 cm. In short rangecommunication in NFC, the interface of the NFC communication part of onedevice is, for example, waved over or brought into contact with theinterface of the NFC communication part of the other device, to bringthe devices closer to each other within a predetermined communicationdistance. This electromagnetically couples the antenna coils of the NFCcommunication parts of the two devices to allow data to be transmittedand received between the NFC communication parts of the two devices.

When the terminal 1 is a smartphone or the like, the terminal 1 includesthe telephone network communication part 430 and carries out acommunication process on a known telephone network by using thetelephone network communication part 430, to enable a voice call or thelike. When the terminal 1 is a smartphone or the like, the terminal 1includes the touch panel 440. The touch panel 440 displays informationon a screen and also receives a touch input operation made on thescreen. When the terminal 1 is a smartphone or the like, the terminal 1includes the sensor 450. The sensor 450 includes, as various kinds ofsensors, an acceleration sensor, a gyro sensor, a GPS sensor, and thelike, for example.

When the terminal 1 has a sleep function, the sleep function temporarilyturns off the display of the touch panel 440 and suspends a process ofthe wireless LAN communication part 410, for example, which reduces thepower consumption.

[Wi-Fi Connection]

Supplementary description is given of a Wi-Fi connection method for thewireless LAN 4. To establish a Wi-Fi connection between a communicationterminal device and an access point, a common Wi-Fi requires informationon the SSID and password of the access point. The communication terminaldevice collects pieces of information on SSIDs available at the spot anddisplays the pieces of information on the screen as candidates. The userof the communication terminal device selects an SSID corresponding tothe access point to be used from among the candidate SSIDs displayed onthe screen and inputs the password associated with the SSID. Thecommunication terminal device transmits the information on the SSID andpassword to the access point. The access point checks the receivedinformation on the SSID and password, permits a connection from thecommunication terminal device when the information is the correctinformation matching the SSID and password of the access point, andestablishes the connection. Note that the terminal 1 may store thepassword in the memory 414 or the secondary storage device 404 inadvance, read the password from the memory 414 or the secondary storagedevice 404 and carry out a connection process.

The SSID stands for a service set ID and is the identifier of an accesspoint and a wireless LAN including the access point. The password is apredetermined password necessary for a connection to the access point.Some wireless LANs do not require a password.

For example, the terminal 1 of the user A of the company A haspermission to connect to the projector 3, which serves as an accesspoint of the wireless LAN 4 communication system of the company A, andthe SSID and password are given in advance to the user A. In addition,the SSID and password are not given to the user B of the company B,which prevents the terminal B from establishing a connection to theaccess point of the wireless LAN 4 communication system of the companyA.

Embodiment 1

With reference to FIG. 5, a communication system, a communicationdevice, and a communication terminal device of Embodiment 1 aredescribed. FIG. 5, similar to FIG. 1, illustrates a state where theterminal 1 of the user A and the terminal 2 of the user B are locatedwithin a hotspot near the projector 3 in the wireless LAN 4. InEmbodiment 1, the terminal 1 of the user A includes the application 15,but the terminal 2 of the user B does not include the application 15. Inother words, as the terminal 2, any existing communication terminaldevice is applicable. The projector 3 includes the application 35. Foreach of the Wi-Fi connection 41 between the terminal 1 and the projector3 and the Wi-Fi connection 42 between the terminal 2 and the projector3, connection information including the SSID and password is required.

[Process Sequence]

FIG. 5 illustrates a configuration and process sequence of thecommunication system of Embodiment 1. S11 and the like indicate steps,such as processes and operations.

(S11) In S11, the terminal 1 of the user A establishes the connection 41to the projector 3 within a hotspot of the wireless LAN 4. A process forestablishing the connection 41 is carried out between the connectionfunction 11 of the terminal land the access point function 32 of theprojector 3. In S11, the user A needs to input, by an operation or thelike, preacquired connection information including the SSID and passworddenoted by PW on the connection 41 to the projector 3. The terminal 1stores and holds the input connection information in the memory in theterminal 1, which makes it possible to omit the input of the connectioninformation in S11 from the next time.

(S12) In S12, the user A starts the application 15 of the terminal 1.Note that the application 15 of the terminal 1 may be started in S11.After the start of the application 15 of the terminal 1, mechanisms suchas control unique to the communication system of Embodiment 1automatically operate.

When the user A gives the user B permission to connect the terminal 2 toand use the projector 3 with the application 15 of the terminal 1activated, the user A establishes the connection 43 with the terminal 2of the user B, using short range communication in NFC. As describedabove, the user A brings the interface of the NFC communication part 420of the terminal 1 close to the interface of the NFC communication part420 of the terminal 2 of the user B. A process for the connection 43 inNFC is carried out between the short range communication function 12 ofthe terminal 1 and the short range communication function 22 of theterminal 2.

In Embodiment 1, the operation for the short range communication in NFCbetween the terminal 1 and the terminal 2 in S12 corresponds topermission from the terminal 1 of the user A for the connection to anduse of the projector 3 by the terminal 2 of the user B.

(S13) In S13, the terminal 1 transmits connection information includingthe SSID and PW for establishing a connection to the projector 3, to theterminal 2 with the connection 43 in S12 established. The terminal 2receives the connection information through the process by the shortrange communication function 12 and stores the connection information inthe memory in the terminal 2.

(S14) In S14, the terminal 2 establishes the Wi-Fi connection 42 to theprojector 3 by the use of the connection information in S13. A processfor establishing the connection 42 is carried out between the connectionfunction 21 of the terminal 2 and the access point function 32 of theprojector 3. In S14, the terminal 2 transmits the connection informationincluding the SSID and PW to the projector 3. When the receivedconnection information matches the connection information of theprojector 3 itself, the projector 3 permits the terminal 2 to establishthe connection 42.

(S15) In S15, the user B uses, through the terminal 2, the displayfunction 31 of the projector 3 with the connection 42 established. Touse the display function 31, data is transferred through the connection42 between the connection function 21 of the terminal 2 and the accesspoint function 32 of the projector 3. For example, the user B transmitsdata, such as material in the terminal 2, a display instruction, and thelike to the projector 3 through the connection 42. The projector 3causes the display function 31 to display data on the screen 313 inaccordance with the data and instruction received from the terminal 2.

(S16) In S16, the application 35 of the projector 3 regularly performscommunication for confirmation with the terminal 1 through theconnection 41. This confirmation is for confirming whether to continueand update or terminate the permission from the terminal 1 of the user Afor the terminal 2 of the user B to connect to and use the projector 3.In other words, this confirmation is for confirming whether to continueor terminate the connection 42 of the terminal 2 of the user B to theprojector 3.

The communication for regular confirmation in S16 is performed atregular intervals. The regular intervals are preset with, for example, 5minutes, 10 minutes, or 20 minutes. Alternatively, the regular intervalsmay be set by a setting function to be described later. The firstcommunication for regular confirmation in S16 may be performed at thetime of establishing the connection 42 in S14 or may be performed afterthe elapse of a certain time period from the establishment of theconnection 42 in S14.

In Embodiment 1, a method in which the projector 3 makes confirmationwith the terminal 1 is employed as the method for confirmation in S16.The projector 3 transmits information on a confirmation request to theterminal 1, and the terminal 1 transmits information on a confirmationresponse to the projector 3. When desiring to continue the permission,the terminal 1 transmits a response indicating the continuance. Whendesiring to terminate the permission, the terminal 1 transmits aresponse indicating the termination.

(S17) When the response from the terminal 1 indicates that thepermission is to be continued, the projector 3 continues the connection42 with the terminal 2 in accordance with the confirmation result inS16. When the response from the terminal 1 indicates that the permissionis to be terminated, the projector 3 terminates the connection 42 withthe terminal 2 in accordance with the confirmation result in S16. Thisbrings the terminal 2 of the user B into a state where the terminal 2 isunable to connect to the projector 3 and use the display function 31.

As described above, in Embodiment 1, connection information is providedto the terminal 2 via the terminal 1 under the permission from the userA. Embodiment 1 can achieve the use as in FIG. 2 through theabove-described process sequence. Note that, to give permission againfrom the terminal 1 of the user A for the terminal 2 of the user B toconnect to and use the projector 3 after the termination of theconnection of the terminal 2 of the user B in S17, a process only needsto be repeated from S11 or S12 as in the same manner as above.

Moreover, to deactivate the control in Embodiment 1, the user Aterminates the application 15 of the terminal 1. Alternatively, thepermission given to the terminal 2 of the user B may be automaticallyterminated at the time when the connection 41 between the terminal 1 ofthe user A and the projector 3 is terminated, so that the connection 42between the terminal 2 and the projector 3 is terminated.

[First Confirmation Method]

In Embodiment 1, the following first confirmation method is used as themethod for confirmation in S16. In the first confirmation method, forthe confirmation in S16, the terminal 1 displays information forconfirmation on the screen of the touch panel 440, for example, throughthe process by the application 15, on the basis of confirmation requestinformation from the application 35 of the projector 3. As theinformation for confirmation, a message such as “Do you want to continuethe permission for the terminal 2 of the user B to connect to and usethe projector 3? Yes/No” is displayed on a pop-up dialog or the like,for example. The user A checks the information for confirmationdisplayed on the terminal 1 and performs an operation of determining,for example, whether to continue or terminate the permission for theterminal 2 of the user B to connect to and use the projector 3, andmaking selection accordingly. The user A presses a button indicating“Yes” or “No” with respect to the information for confirmation on thescreen of the touch panel 440, for example.

According to the operation of selection through the terminal 1 by theuser A, the terminal 1 transmits response information on theconfirmation corresponding to the selection, to the projector 3. Whenthe response information indicates, for example, “Yes”, in other words,the selection is made so as to continue the permission, the projector 3continues the connection 42 with the terminal 2 in S17. When theresponse information indicates, for example, “No”, in other words, theselection is made so as to terminate the permission, the projector 3terminates the connection 42 with the terminal 2 in S17. Note that, whenthe user A does not perform any selection operation through the terminal1 and a state in which the terminal 1 does not make any response to theprojector 3 continues for a predetermined time period or longer, theprojector 3 may terminate the connection 42 with the terminal 2.

[Second Confirmation Method]

In a modified example of Embodiment 1, a second confirmation methoddescribed below may be used as the method for confirmation in S16. Inthe second confirmation method, for the confirmation in S16, theapplication 35 of the projector 3 transmits predetermined informationfor confirmation to the terminal 1 on the condition that the connection41 in S11 has been established. When the application 15 of the terminal1 receives the predetermined information for confirmation from theprojector 3, the application 15 automatically transmits predeterminedresponse information for confirmation. This eliminates the need for theuser A to perform and hence to be aware of any operation.

When the application 35 of the projector 3 receives the predeterminedresponse information for confirmation from the terminal 1, theapplication 35 can confirm, for example, that the terminal 1 and theapplication 15 are running and are located within the hotspot of thewireless LAN 4, and the connection 41 is continued. In other words, theprojector 3 can confirm that the terminal 1 of the user A and theterminal 2 of the user B are located close to each other, for example.Hence, the projector 3 determines that the permission given to theterminal 2 of the user B by the terminal 1 of the user A is continued onthe basis of this confirmation and continues the connection 42 with theterminal 2 in S17.

When having not received the predetermined response information forconfirmation from the terminal 1, the application 35 of the projector 3can determine, for example, that the terminal 1 and the application 15have yet to be activated or are not located within the hotspot of thewireless LAN 4, or the connection 41 is not continued. The projector 3is unable to confirm, for example, a state where the terminal 1 of theuser A and the terminal 2 of the user B are located close to each other,hence determines that the permission given to the terminal 2 of the userB by the terminal 1 of the user A is to be terminated, and terminatesthe connection 42 with the terminal 2 in S17.

In the communication for confirmation between the projector 3 and theterminal 1 in S16 described above, a predetermined number of retries maybe allowed in consideration of the possibility of communicationfailures.

[Control with Sleep Function]

As another modified example of Embodiment 1, control, taking intoaccount a running state and sleep state of the terminal 1, is performedin association with the confirmation method in S16 described above. Whenthe terminal 1 is a smartphone or the like, the terminal 1 oftenincludes a known sleep function. Specifically, when the terminal 1 whichhas the sleep function has not received any input operation or the likefrom a user for a predetermined time period or longer in a normal state,the terminal 1 automatically changes to a sleep state, which is alow-power-consumption mode. Depending on the sleep function, the displayof the touch panel 440 is turned off, and the operation of the radiopart 410 is stopped, in the sleep state, for example. The terminal 1returns from the sleep state to the normal state in response to an inputoperation or the like by the user.

In the sleep state, the terminal 1 may be unable to receive anycommunication information from the external projector 3 via the wirelessLAN 4, or may be unable to process information even if the terminal 1has received the information, for example. In this case, the terminal 1may be unable to perform communication for confirmation with theprojector 3 in S16 described above.

In view of this, in the communication system of the modified example ofEmbodiment 1, the following control is performed for the case of theterminal 1 including the sleep function. The terminal 1 transitions to anon-sleep state prior to S16 so as not to be in the sleep state at thetime of receiving confirmation request information from the projector 3in S16. The non-sleep state mentioned here is a state where the terminal1 does not transition to the sleep state even when a state whereterminal 1 has not received any input operation from a user continuesand is capable of performing wireless communication with the externalprojector 3. The application 15 of the terminal 1 causes, in advance,the terminal 1 to transition to the non-sleep state after the activationof the application 15 or short range communication in S12, for example,and maintains the connection 41 in S11.

This operation allows the terminal 1 to receive confirmation requestinformation from the projector 3 in S16 and send a response.Subsequently, the terminal 1 returns from the non-sleep state to thenormal state triggered by termination of the connection 41 with theprojector 3, termination of the permission given to the terminal B ofthe user B, termination of the application 15, or the like.

[Setting Function]

The application 15 of the terminal 1 or the application 35 of theprojector 3 has a setting function enabling a user to make settings ofthe functions of Embodiment 1. For example, the user A can make settingsfor the contents of control of the functions of Embodiment 1 in responseto a setting operation using this setting function. With the settingfunction, it is possible to make a time at which the regularconfirmation in S16 is performed. For example, the user can set timeintervals at which the regular confirmation is performed, at a desiredtime period, such as “5 minutes” or “10 minutes” on a setting screenprovided by the application 15. Furthermore, the method for confirmationto be used in S16 may be selected from the first confirmation method andthe second confirmation method by the user through the setting function.

[Effects and the Like]

The communication system of Embodiment 1 provides the function ofenabling the terminal 2 of the user B of the external company B totemporarily connect to and use the projector 3 via the wireless LAN 4 ofthe company A, under the permission from the terminal 1 of the user A ofthe company A. The use of Embodiment 1 can achieve convenience throughthis function and ensure security in this case.

In the present embodiment, the user A and the user B can use theabove-described functions through simple operations and settings. InEmbodiment 1, the user A can permit the terminal 2 of the user B toconnect to and use the projector 3 through simple operations ofactivating the application 15 of the terminal 1 and performing shortrange communication with the terminal 2.

Moreover, the present embodiment can ensure security in thecommunication system by performing control that enables the terminal 2of the user B to temporarily connect to and use the projector 3 underthe permission given on the condition that the terminal 1 of the user Aand the terminal 2 of the user B are located close to each other.Particularly in Embodiment 1, when the permission is confirmed throughthe regular confirmation in S16, the connection 42 of the terminal 2 ofthe user B is continued, and the connection 42 is terminated when thepermission is not confirmed. Hence, it is possible to prevent such asituation as to allow the terminal 2 of the user B of the company B toindependently connect to and use the projector 3 in the communicationsystem via the wireless LAN 4 of the company A.

First Modified Example of Embodiment 1

FIG. 6 illustrates a process sequence in a configuration of acommunication system of a first modified example of Embodiment 1. Thecommunication system of Embodiment 1 in FIG. 5 described above has aconfiguration in which the projector 3 plays a major role in performingthe confirmation in S16. In contrast to this, the communication systemof the first modified example of Embodiment 1 illustrated in FIG. 6 hasa different configuration in which the terminal 1 of the user A plays amajor role in performing the confirmation in S16.

In FIG. 6, steps S11 to S15 are the same as those in FIG. 5. In step S16a, the terminal 1 of the user A performs, by itself, regularconfirmation regarding permission given to the terminal 2 of the user B.In the confirmation in S16 a, for example, the first confirmationmethod, the second confirmation method, or the like can be employed asdescribed above. In the first confirmation method, the application 15 ofthe terminal 1 displays information for confirmation on the screen ofthe terminal 1 at regular timings from the time of establishing theconnection 42 of the terminal 2 in S14. The user A checks theinformation for confirmation on the screen and makes an input operationfor selection corresponding to continuance or termination of thepermission given to the terminal B of the user B.

When the above input from the user A indicates that the permission is tobe continued, the terminal 1 does nothing, which results in noinformation being transmitted to the projector 3. When the above inputfrom the user A indicates that the permission is to be terminated as instep S16 b, the terminal 1 transmits information indicating terminationof the permission to the projector 3. When receiving informationindicating termination of the permission in S16 b from the terminal 1,the projector 3 terminates the connection 42 with the terminal 2. Aslong as the projector 3 does not receive information indicatingtermination of the permission from the terminal 1, the projector 3continues the connection 42 with the terminal 2.

Alternatively, the terminal 1 may be configured to transmit informationindicating continuance of the permission to the projector 3 when theabove input from the user A indicates continuance of the permission, andthe projector 3 terminates the connection 42 with the terminal 2 whenthe projector 3 has not received information indicating continuance ofthe permission for a predetermined time period or longer.

Second Modified Example of Embodiment 1

FIG. 7 illustrates a configuration of a communication system of a secondmodified example of Embodiment 1. In the communication system of thesecond modified example of Embodiment 1 illustrated in FIG. 7, theprojector 3 is constituted of two devices, instead of a single device.In the second modified example, the projector 3 of Embodiment 1 isconstituted of two separate devices, in other words, a projector device3A which has the display function 31 and an access point device 3B whichhas the access point function 31 of the wireless LAN 4, and the twodevices coordinate with each other through communication.

The projector device 3A and the access point device 3B establish aconnection 44 in a predetermined communication system and performcommunication through the connection 44 for the coordination. Forexample, the projector device 3A and the access point device 3B includea wired LAN interface 330 as in FIG. 3 and carry out a communicationprocess through the connection 44 via a wired LAN. The access pointdevice 3B and the projector device 3A may include the above-describedapplication 35.

The projector device 3A provides the display function 31, and the accesspoint device 3B provides the access point function 31 of the wirelessLAN 4 and a router function.

The terminal 1 of the user A uses the display function 31 of theprojector device 3A through the connection 41 with the access pointdevice 3B. The terminal 2 of the user B uses the display function 31 ofthe projector device 3A through the connection 42 with the access pointdevice 3B, under the permission from the terminal 1 of the user A, inthe same manner as above.

Embodiment 2

With reference to FIG. 8, a communication system and the like ofEmbodiment 2 are described. In the communication system of Embodiment 2,the projector 3 is provided with a permission list 52, in which piecesof information on terminals to be given permission for a connection toand use of the projector 3 are registered, as in FIG. 8. The projector 3determines and controls a connection thereto and use thereof from theterminal 2 of the user B on the basis of the information in thepermission list 52.

[List]

In the communication system of Embodiment 2, the projector 3 includes alist 51 and the permission list 52 as in FIG. 8. The access pointfunction 32 manages the list 51. The access point function 32 or theapplication 35 manages the permission list 52.

In the list 51 as a first list, registered are pieces of information onthe MAC addresses or the like of terminals of users each givenpermission for regular connection via the wireless LAN 4. In the exampleof the present embodiment, pieces of information including the MACaddresses of terminals of employees including the MAC address of theterminal 1 of the user A of the company A are registered in the list 51in advance. Assume that the MAC address of the terminal 1 of the user Ais denoted by Ma, and the MAC address of the terminal 2 of the user B isdenoted by Mb.

The permission list 52 is a list provided, as a second list, for uniquecontrol in Embodiment 2. In the permission list 52, pieces ofinformation on terminals of users each given permission for a temporaryconnection to and use of the projector 3 via the wireless LAN 4 underthe permission from the terminal 1 of the user A are registered. In theexample of the present embodiment, information including the MAC addressof the terminal 2 of the user B of the company B is registered in thepermission list 52.

In Embodiment 2, the terminal 1 includes the application 15. Theprojector 3 may include the application 35, but does not need to includethe application 35. The application 15 and the application 35 carry outa process different for each embodiment.

[Process Sequence]

FIG. 8 illustrates a configuration and process sequence of thecommunication system of Embodiment 2. S21 and the like indicate steps.S21 to S23 are the same as S11 to S13 in Embodiment 1.

(S21) In S21, the terminal 1 of the user A and the projector 3 establishthe Wi-Fi connection 41. Connection information for this connection 41includes the SSID and password denoted by PW. In this step, the terminal1 transmits Ma, which is its MAC address, and the projector 3 confirmswhether information corresponding to the received Ma is registered inthe list 51. The projector 3 does not give connection permission to aterminal that is not registered.

(S22) In S22, the user A establishes the connection 43 in NFC betweenthe terminal 1 and the terminal 2 of the user B with the application 15of the terminal 1 activated. This short range communication correspondsto permission from the terminal 1 of the user A for the terminal 2 ofthe user B to connect to and use the projector 3.

(S23) In S23, the terminal 1 transmits connection information includingthe SSID and password to the terminal 2 with the connection 43established. The terminal 2 receives the connection information andstores the connection information in the memory.

(S24) Moreover, in S24, the terminal 1 acquires information on Mb, whichis the MAC address of the terminal 2, from the terminal 2 through theconnection 43. The terminal 1 stores the information on Mb in thememory.

(S25-1) In S25-1, the terminal 1 transmits information including Mb,which is the MAC address of the terminal 2, to the projector 3 throughthe connection 41.

(S25-2) In S25-2, the projector 3 registers the information includingMb, which is the MAC address of the terminal 2, received from theterminal 1 so as to add the information to the permission list 52. Thestate in which the MAC address is registered corresponds to the state ofhaving control for permitting the connection 42 between the terminal 2and the projector 3. In this step, the projector 3 registers, in thepermission list 52, only a MAC address transmitted from a terminalregistered in the list 51.

(S26) In S26, the terminal 2 establishes the Wi-Fi connection 42 withthe projector 3 by the use of the SSID and password, which are theconnection information in S23. In S26, the projector 3 refers to theinformation in the permission list 52 and confirms whether or not theMAC address of a terminal to be connected is registered. In this step,Mb, which is the MAC address of the terminal 2, is already registered inthe permission list 52 in S25-2. Hence, the projector 3 permits theterminal 2 to establish the connection 42 in S26. The projector 3 doesnot permit a terminal whose MAC address is not registered in thepermission list 52 to establish the connection 42.

(S27) In S27, the terminal 2 uses the display function 31 of theprojector 3 through the connection 42.

(S28-1) In S28-1, the user A confirms whether to continue or terminatethe permission for the terminal 2 of the user B to connect to and usethe projector 3. The user A does not make any changes when thepermission is to be continued. When the permission is to be terminatedin S28-1, in other words, when the connection 42 is to be terminated,the user A performs an input operation corresponding to the terminationof the permission given to the terminal 2 of the user B, in other words,termination of the connection 42, on the screen provided by theapplication 15 of the terminal 1.

(S28-2) In S28-2, the application 15 of the terminal 1 transmitsinformation indicating the termination of the permission given to theterminal 2 of the user B to the projector 3 through the connection 41 inresponse to the input operation for the termination of the permission inS28-1.

(S28-3) In S28-3, when the projector 3 receives the informationindicating the termination of the permission given to the terminal 2 ofthe user B from the terminal 1, the projector 3 deletes the informationon Mb, which is the MAC address of the terminal 2, from the permissionlist 52. This state in which the registration of the MAC address isdeleted corresponds to the state of having control for not permittingthe connection 42 between the terminal 2 and the projector 3.

(S29) In S29, as a result of the registration of the MAC address of theterminal 2 being deleted from the permission list 52 in S28-3, theprojector 3 terminates the connection 42 with the terminal 2. Thisoperation brings the terminal 2 of the user B into a state where theterminal 2 is unable to establish the connection 42 with the projector 3and use the display function 31.

As described above, in Embodiment 2, the connection to and use of theprojector 3 by the terminal 2 of the user B is controlled in accordancewith confirmation of the MAC address obtained from the terminal 2 of theuser B via the terminal 1 of the user A.

[Termination Upon Power-Off]

As a modified example of Embodiment 2, the following method can also beemployed for the process of terminating the connection 42 of theterminal 2 of the user B through registration, deletion, andconfirmation of information in the above permission list 52.Specifically, the projector 3 deletes the information on the MAC addressof the terminal 2 registered in the permission list 52 in an operationtermination process upon power-off through an operation made by the userA or the like. Alternatively, the projector 3 initializes the permissionlist 52 at the time of power-off to delete all the pieces ofinformation. After the deletion, the projector 3 does not permit theconnection 42 of the terminal 2 whose MAC address has yet to beregistered in the permission list 52 after power-on.

As a modified example of Embodiment 2, the following method forconfirmation and termination can also be employed. Specifically, in thismethod, the projector 3 performs regular confirmation with the terminal1 as in S16 in Embodiment 1, instead of the steps indicated in S28-1 toS28-3 and the like. When the permission is to be terminated as a resultof the regular confirmation, the projector 3 deletes the information onthe MAC address of the terminal 2 from the permission list 52 andterminates the connection 42 with the terminal 2.

As a modified example of Embodiment 2, the projector 3 may hold a listincluding a combination of the list 51 and the permission list 52.Specifically, in this list, information on the terminals each givenpermission for a connection, including the MAC address of the terminal 1of the user A and the like each given permission for a regularconnection and the MAC address of the terminal 2 of the user B and thelike each given permission for a temporary connection is registered andmanaged.

Modified Example of Embodiment 2

FIG. 9 illustrates a configuration and process sequence in acommunication system of a modified example of Embodiment 2. In thecommunication system of this modified example, the terminal 1 of theuser A, instead of the projector 3, holds the permission list 52. Theapplication 15 manages the permission list 52. The projector 3 holds thelist 51. S21 to S24 in FIG. 9 are the same as S21 to S24 in FIG. 8.

In S25 in FIG. 9, the application 15 of the terminal 1 registersinformation on Mb, which is the MAC address of the terminal 2 to bepermitted, in the permission list 52. In S26, the terminal 2 establishesthe connection 42 with the projector 3. In S27, the terminal 2 uses thedisplay function 31 of the projector 3 through the connection 42.

In S28-1, when terminating permission for the terminal B of the user Bto connect to and use the projector 3, the user A performs an inputoperation for terminating the permission on the screen provided by theapplication 15 of the terminal 1. In S28-2, in response to the operationin S28-1, the application 15 of the terminal 1 deletes the informationon Mb, which is the MAC address of the terminal 2 whose permission is tobe terminated, from the permission list 52.

In contrast, the projector 3 performs regular confirmation with theterminal 1 as to whether to continue or terminate the permission for theterminal 2 of the user B to connect to and use the projector 3. InS29-1, the projector 3 transmits information on regular confirmation tothe terminal 1 through the connection 41. The terminal 1 transmitsresponse information for the regular confirmation to the projector 3 onthe basis of the state of the permission list 52. In S29-1, for example,the projector 3 refers to the information in the permission list 52 inthe terminal 1 and confirms whether or not the MAC address of theterminal 2 is registered in the permission list 52. When the MAC addressof the terminal 2 is registered in the permission list 52, the projector3 continues the connection 42 with the terminal 2. When the MAC addressis not registered, the projector 3 terminates the connection 42 with theterminal 2.

The communication for the regular confirmation in S29-1 is performed atregular intervals as in S16 in Embodiment 1. Note that the firstcommunication for the regular confirmation in S29-1 is performed at thetime of establishing the connection 42 in S26. In this step, controlusing the sleep function may be performed in the terminal 1 as describedabove.

The regular confirmation in S29-1 described above may be performed insuch a way as to notify, from the terminal 1, the projector 3 ofinformation on the contents in the permission list 52 in a push-typemanner. For example, the terminal 1 may instruct the projector 3 toterminate the permission for the terminal 2 to connect to and use theprojector 3, in other words, to terminate the connection 42, immediatelyafter the deletion of the information on the MAC address of the terminal2 from the permission list 52 in S28-2. The projector 3 terminates theconnection 42 with the terminal 2 in accordance with the instruction.

Embodiment 3

With reference to FIG. 10, a communication system and the like ofEmbodiment 3 are described. In Embodiment 3, a one-time password isissued for control of permission for the terminal B of the user B toconnect to and use the projector 3. This one-time password isinformation prepared for control unique to Embodiment 3 and differentfrom the above-described password associated with an SSID.

[Process Sequence]

FIG. 10 illustrates a configuration and process sequence of thecommunication system of Embodiment 3. S31 and the like indicate steps.

(S31) In S31, the terminal 1 of the user A establishes the Wi-Ficonnection 41 with the projector 3 as in the same manner as above andstores the SSID and password denoted by PW, which are connectioninformation.

(S32) In S32, when permitting the terminal 2 of the user B to connect toand use the projector 3, the user A requests, through the terminal 1,the projector 3 to issue a one-time password for the permission. Theone-time password is denoted by OTPW. In S32, for example, the user Aperforms an input operation for the permission on the screen provided bythe application 15 of the terminal 1, thereby causing the application 15of the terminal 1 to transmit information on the issue request of aone-time password to the projector 3 through the connection 41.

(S33) In S33, upon receipt of the information on the issue request of aone-time password in S32, the projector 3 causes the application 35 toissue a one-time password and transmits the one-time password to theterminal 1 through the connection 41. The terminal 1 receives theone-time password from the projector 3 and stores the one-time passwordin the memory. Alternatively, the access point function 32 may issue aone-time password.

In a configuration where the projector 3 includes the short rangecommunication function 34, the terminal 1 may transmit, to the projector3, information on the issue request of a one-time password in S32described above, through short range communication with the projector 3in the communication in S32, and the terminal 1 may receive the one-timepassword from the projector 3 through short range communication with theprojector 3 in the communication in S33.

(S34) In S34, the terminal 1 establishes the connection 43 with theterminal 2 in NFC.

(S35) In S35, the terminal 1 transmits connection information includingthe SSID in S31 described above and the one-time password denoted byOTPW and acquired in S33, to the terminal 2 through the connection 43.The terminal 2 stores the received connection information including theSSID and one-time password in the memory.

(S36) In S36, the terminal 2 establishes the Wi-Fi connection 42 withthe projector 3 by the use of the SSID and one-time password, which arethe connection information acquired in S35. In S36, the terminal 2transmits the one-time password to the projector 3. The application 35of the projector 3 confirms whether the one-time password received fromthe terminal 2 matches the one-time password issued in S33. Theapplication 35 of the projector 3 permits the connection 42 with theterminal 2 when the one-time passwords match each other, whereas theapplication 35 does not permit the connection 42 with the terminal 2when the one-time passwords do not match each other.

(S37) In S37, the terminal 2 uses the display function 31 of theprojector 3 through the connection 42.

(S38) In S38, the user A confirms whether to continue or terminate thepermission for the terminal 2 of the user B to connect to and use theprojector 3, and the terminal 1 transmits information indicating thecontinuance or termination of the permission to the projector 3. Forexample, when terminating the permission, the user A performs, as in thesame manner as above, an input operation for terminating the permissionon the screen provided by the application 15 of the terminal 1. Thisoperation causes the application 15 of the terminal 1 to transmitinformation indicating the termination of the permission to theprojector 3.

(S39) In S39, the projector 3 continues or terminates the connection 42with the terminal 2 in accordance with the information on theconfirmation and instruction regarding whether to continue or terminatethe permission, from the terminal 1 in S38.

Alternatively, for example, the projector 3 may keep the issued one-timepassword valid in accordance with the information indicating continuanceof the permission from the terminal 1 and make the issued one-timepassword invalid in accordance with the information indicatingtermination of the permission.

Alternatively, for example, the projector 3 may issue a new one-timepassword as an update process in accordance with information indicatingcontinuance of the permission from the terminal 1 and may discard theissued one-time password in accordance with the information indicatingtermination of the permission.

The processes in S38 and S39 described above may be configured to causethe projector 3 to make regular confirmation with the terminal 1 as inthe same manner as above.

As described above, in Embodiment 3, the connection to and use of theprojector 3 by the terminal 2 of the user B is controlled in accordancewith confirmation of the one-time password provided to the terminal 2 ofthe user B via the terminal 1 of the user A.

Thereafter, the projector 3 or the terminal 1 discards or invalidatesthe above issued one-time password upon power-off of the projector 3,the elapse of a predetermined time period, or the like.

Embodiment 4

With reference to FIG. 11, a communication system and the like ofEmbodiment 4 are described. In Embodiment 4, control is performed byregistering information on the MAC address of the terminal 2 in thepermission list 52 of the projector 3, as in Embodiment 2. In Embodiment4, short range communication with the terminal 2 of the user B isperformed by the use of the short range communication function 34 of theprojector 3. The projector 3 of Embodiment 4 includes theabove-described short range communication function 43.

[Process Sequence]

FIG. 11 illustrates a configuration and process sequence of thecommunication system of Embodiment 4. S41 and the like indicate steps.

(S41) In S41, the terminal 1 and the projector 3 establish the Wi-Ficonnection 41.

(S42) In S42, when permitting the terminal 2 of the user B to connect toand use the projector 3, the user A causes the terminal 2 of the user Bto perform short range communication with the projector 3. In FIG. 11,45 denotes a connection using short range communication in NFC betweenthe short range communication function 22 of the terminal 2 and theshort range communication function 34 of the projector 3. For example,the user B brings the interface of the short range communicationfunction 22 of the terminal 2 close to the interface of the short rangecommunication function 34 of the projector 3. This operation establishesthe connection 45 in NFC.

(S43) In S43, the projector 3 acquires information on Mb, which is theMAC address of the terminal 2, from the terminal 2 with the connection45 in S42 established.

(S44) In S44, the access point function 32 or the application 35 of theprojector 3 transmits connection information including the SSID andpassword denoted by PW for the connection via the wireless LAN 4, to theterminal 2 with the connection 45 in S42 established. The terminal 2receives the connection information and stores the connectioninformation in the memory. In S44, the projector 3 may communicate withthe terminal 1 to confirm if the projector 3 may transmit the connectioninformation to the terminal 2.

(S45) In S45, the projector 3 registers the information including Mb,which is the MAC address of the terminal 2, acquired in S43, in thepermission list 52. Note that the projector 3 holds the list 51 and thepermission list 52 in the same manner as above.

(S46) In S46, the terminal 2 establishes the Wi-Fi connection 42 withthe projector 3 by the use of the connection information including theSSID and PW in S43.

(S47) In S47, the terminal 2 uses the display function 31 of theprojector 3 through the connection 42.

(S48-1) In S48-1, when terminating the permission for the terminal 2 ofthe user B to connect to and use the projector 3, the user A performs aninput operation for terminating the permission on the screen provided bythe application 15 of the terminal 1 in the same manner as above. Thisoperation causes the application 15 of the terminal 1 to transmitinformation indicating the termination of the permission to theprojector 3.

(S48-2) In S48-2, in accordance with the information indicating thetermination of the permission transmitted from the terminal 1, theprojector 3 deletes the information on Mb, which is the MAC address ofthe terminal 2, from the permission list 52.

(S49) In S49, as a result of the MAC address of the terminal 2 beingdeleted from the permission list 52 in S47-2, the projector 3 terminatesthe connection 42 with the terminal 2, which makes the terminal 2 of theuser B unable to connect to and use the projector 3.

The process for confirmation in S48-1 and S48-2 described above may beconfigured to cause the projector 3 to make regular confirmation withthe terminal 1 in the same manner as above. In this step, control usingthe sleep function may be performed in the terminal 1 as describedabove.

Subsequently, the projector 3 may delete the information on the MACaddress of the terminal 2 registered in the permission list 52 uponpower-off or the like in the same manner as above.

Note that, although short range communication is not performed betweenthe terminal 1 and the terminal 2 in Embodiment 4, predeterminedinformation for control may be transmitted and received between theterminal 1 and the terminal 2 using short range communication as amodified example of Embodiment 4.

Embodiment 5

With reference to FIG. 12, a communication system and the like ofEmbodiment 5 are described. Embodiment 5 has a configuration in which aone-time password for control is used, as a configuration common toEmbodiment 3 and has a configuration in which short range communicationis performed between the terminal 2 of the user B and the projector 3 asa configuration common to Embodiment 4.

[Process Sequence]

FIG. 12 illustrates a configuration and process sequence of thecommunication system of Embodiment 5. S51 and the like indicate steps.

(S51) In S51, the terminal 1 establishes the Wi-Fi connection 41 withthe projector 3.

(S52) In S52, the terminal 2 of the user B is caused to perform shortrange communication with the projector 3. The terminal 2 of the user Bestablishes the connection 45 in NFC with the projector 3.

(S53) In S53, the terminal 2 transmits, to the projector 3, informationon an issue request of a one-time password denoted by OTPW regardingpermission for a connection via the wireless LAN 4, with the connection45 in S52 established.

(S54) In S54, in response to the issue request in S53, the application35 of the projector 3 issues a one-time password.

The access point function 32 of the projector 3 transmits connectioninformation including the SSID and one-time password for the connectionvia the wireless LAN 4, to the terminal 2 through the connection 45.

Note that, in this step, the projector 3 may communicate with theterminal 1 to confirm if the projector 3 may transmit the connectioninformation including the one-time password to the terminal 2.

(S55) In S55, the terminal 2 establishes the Wi-Fi connection 42 withthe projector 3 by the use of the above-mentioned connection informationincluding the SSID and one-time password. The projector 3 confirms theone-time password in the same manner as above and then permits theconnection 42.

(S56) In S56, the terminal 2 uses the display function 31 of theprojector 3 through the connection 42.

(S57) In S57, the user A confirms whether to continue or terminate thepermission for the terminal 2 of the user B to connect to and use theprojector 3. For example, when terminating the permission, the user Aperforms an input operation for terminating the permission on the screenprovided by the application 15 of the terminal 1 in the same manner asabove. This operation causes the application 15 of the terminal 1 totransmit information indicating the termination of the permission to theprojector 3.

(S58) In S58, the projector 3 continues or terminates the connection 42with the terminal 2 in accordance with the information in S57. In thisstep, the one-time password issued in S54 is made invalid.

S57 and S58 described above may be configured so that the projector 3makes regular confirmation with the terminal 1 in the same manner asabove. In this step, control using the sleep function may be performedin the terminal 1 as described above.

Embodiment 6

With reference to FIG. 13, a communication system and the like ofEmbodiment 6 are described. Other communication systems than NFC can beemployed as a short range communication system between the terminal 1and the terminal 2 and as a short range communication system betweeneach communication terminal device and the projector 3 in Embodiment 1and the like described above. Embodiment 6 is a configuration in whichbar code recognition system using a camera is employed, as a short rangecommunication system between the terminal 1 and the terminal 2.

In Embodiment 6, the terminal 2 includes a camera. The terminal 2 has acamera control function as the short range communication function 22.The short range communication function 22 carries out a process ofreading information obtained by capturing an image by the use of thecamera, and the like. As the camera and the control function of theterminal 2, a camera included in an existing smartphone or the like andthe function of controlling the camera can be employed.

[Process Sequence]

FIG. 13 illustrates a configuration and process sequence of thecommunication system of Embodiment 6. S61 and the like indicate steps.

(S61) In S61, the terminal 1 establishes the Wi-Fi connection 41 withthe projector 3.

(S62) In S62, when permitting the terminal 2 of the user B to connect toand use the projector 3, the user A performs an operation for displayingconnection information by the use of the application 15 of the terminal1. The application 15 of the terminal 1 carries out a process ofconverting the connection information including the SSID and passwordfor the wireless LAN 4 through the connection 41 in S61, into the dataof, for example, a two-dimensional bar code and displaying the data onthe screen provided by the application 15 of the terminal 1.

(S63) In S63, the user B performs, as short range communication betweenthe terminal 1 and the terminal 2, an operation for recognizing the barcode on the screen provided by the application 15 of the terminal 1, bythe use of the camera of the terminal 2. The terminal 2 reads the barcode from the image captured by the camera and acquires connectioninformation including the SSID and password by converting the read barcode. The terminal 2 stores the acquired connection information in thememory.

The subsequent steps are mostly the same as those in the above-describedembodiments. In S64, the terminal 2 establishes the Wi-Fi connection 42with the projector 3 by the use of the connection information in S63. InS65, the terminal 2 uses the display function 31 of the projector 3through the connection 42. In S66, confirmation whether to continue orterminate the permission is performed between the terminal 1 and theprojector 3 in a predetermined method in the same manner as above. Onthe basis of the confirmation, the projector 3 continues or terminatesthe connection 42 with the terminal 2 in S67.

Note that, in a case where the terminal 2 does not have the function ofcontrolling a process for reading connection information with the camerain Embodiment 6, a dedicated application which has such a function maybe temporarily installed.

Modified Example of Embodiment 6

As a modified example of Embodiment 6, a configuration may be made sothat short range communication using a camera is performed between theterminal 2 of the user B and the projector 3. In this modified example,connection information is displayed on a screen of the projector 3instead of displaying the connection information on the screen providedby the application 15 of the terminal 1. The projector 3 converts theconnection information into, for example, a bar code, through a processby the application 35 and displays the converted information on thedisplay of a screen 313, an operation panel, or the like.

The terminal 2 acquires the connection information by capturing, withthe camera, an image of the bar code on the screen displayed by theprojector 3 and reading the bar code. The subsequent steps aresubstantially the same as those described above. The terminal 2establishes the connection 42 with the projector 3 by the use of theconnection information and uses the display function 31. The projector 3continues or terminates the connection 42 with the terminal 2 inresponse to the confirmation as to whether to continue or terminate thepermission between the terminal 1 and the projector 3.

[Effects and the Like]

As described above, the communication system of each embodiment providesthe function of enabling the terminal 2 of the extra-company user B totemporarily connect to and use the projector 3 via the wireless LAN 4under permission from the terminal 1 of the intra-company user A. Eachembodiment can achieve convenience through this function and ensuresecurity in such a case.

The technology of the embodiments is a mechanism for the terminal 1 ofthe user A to permit the terminal 2 of the user B to connect to and usethe projector 3, in a situation where the intra-company user A and theextra-company user B are located close to each other and the user Aknows the existence of the user B. With the mechanism includingpermission based on the situation and confirmation as to whether tocontinue or terminate the permission, security is ensured. In addition,control including this permission does not require many operations, suchas setting, and can be easily used only by an operation of anapplication, an operation for short range communication, and the like.

The present invention has been described in details on the basis of theembodiments. However, the present invention is not limited to theabove-described embodiments, and various changes can be made withoutdeparting from the gist of the present invention. As other embodiments,a configuration made by combining functions and elements of each of theabove-described embodiments and a configuration made by omitting some ofthe functions and elements of each embodiment are possible.

In a communication system of another embodiment, information forconfirmation may be displayed on the screen for the projector 3 insteadof the screen provided by the application 15 of the terminal 1 when aninput operation for continuing or terminating permission is performed bythe terminal 1 of the user A, as in, for example, S28-1 in FIG. 8described above. For example, the projector 3 displays information onconfirmation as to continue or terminate the permission for the terminal2 of the user B to connect to and use the projector 3, in the display onthe screen 313 through the process by the application 35. The displayedinformation provides options such as “yes/no” or “continue/terminate”,for example.

The user A checks the information for confirmation displayed on thescreen of the projector 3 and inputs instruction information to theprojector 3. For example, the terminal 1 may be used as a device havinga function corresponding to a remote controller of the projector 3, bythe application 15. The user A inputs an instruction on the screenprovided by the application 15 of the terminal 1. This operation causesthe terminal 1 to transmit the instruction information to the projector3 through the connection 41. The projector 3 receives the instructioninformation from the terminal 1 and performs a process for, for example,continuing or terminating the connection, in accordance with theinstruction.

A communication system of another embodiment is implemented withmultiple functions and methods of the above-described multipleembodiments, to allow the user to select a function and method to usethrough a setting function. For example, the user A selects and sets themethod of Embodiment 1 from among multiple methods displayed as optionsin a setting window, through the setting function provided by theapplication 15 of the terminal 1 or the application 35 of the projector3. With this setting made, control as in FIG. 5 of Embodiment 1 isemployed.

In each embodiment, not only does the terminal 1 include the dedicatedapplication 15, but also the terminal 2 may include a dedicatedapplication for unique control. In this case, the application 15 of theterminal 1 and the application of the terminal 2 coordinate with eachother.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a display device, a wireless LAN,a system for assisting in meetings and conferences, and the like.

REFERENCE SIGNS LIST

-   1 Terminal-   2 Terminal-   3 Projector-   4 Wireless LAN-   5 Communication network-   11, 21 Connection function-   12, 22, 34 Short range communication function-   15 Application-   31 Display function-   32 Access point function-   33 Router function-   35 Application-   41, 42, 43, 44, 45 Connection

1. A communication system comprising: a first communication terminaldevice having a wireless LAN connection function; a second communicationterminal device having a wireless LAN connection function; and acommunication device having a wireless LAN access point function and adisplay function, the first communication terminal device connecting tothe communication device via a wireless LAN, the second communicationterminal device connecting, under permission from the firstcommunication terminal device, to the communication device via thewireless LAN and using the display function of the communication devicethrough the connection, the first communication terminal device and thecommunication device communicating with each other to confirm whetherthe permission for the second communication terminal device to connectto and use the communication device is to be continued or terminated,and, in response to a termination of the permission, the communicationdevice terminating the connection with the second communication terminaldevice via the wireless LAN to make the second communication terminaldevice unable to use the display function.
 2. The communication systemaccording to claim 1, wherein, for the permission, the firstcommunication terminal device transmits, to the second communicationterminal device, connection information necessary for a connection viathe wireless LAN through short range communication with the secondcommunication terminal device, and the second communication terminaldevice connects to the communication device via the wireless LAN byusing the connection information.
 3. The communication system accordingto claim 1, wherein the communication device regularly confirms, withthe first communication terminal device, whether to continue orterminate the permission, after the connection to the secondcommunication terminal device, and continues the connection with thesecond communication terminal device upon the permission being to becontinued, while terminating the connection with the secondcommunication terminal device upon the permission being to beterminated.
 4. The communication system according to claim 1, whereinthe first communication terminal device regularly confirms, with a user,whether to continue or terminate the permission, after the connection tothe second communication terminal device, and transmits informationindicating termination of the permission, to the communication deviceupon the permission being to be terminated, and, upon receiving theinformation indicating termination of the permission, the communicationdevice terminates the connection with the second communication terminaldevice.
 5. The communication system according to claim 1, wherein, forthe confirmation, the first communication terminal device displays, fora user, information for confirming whether to continue or terminate thepermission on a display screen, receives an input made through a useroperation for continuing or terminating the permission, and transmitsinformation indicating that the permission is to be continued orterminated in accordance with the input to the communication device. 6.The communication system according to claim 1, wherein, for theconfirmation, the communication device transmits information forconfirming whether to continue or terminate the permission, to the firstcommunication terminal device, upon receiving the information for theconfirmation, the first communication terminal device transmits responseinformation to the communication device, and the communication devicedetermines that the permission is to be continued upon receiving theresponse information from the first communication terminal device, anddetermines that the permission is to be terminated and terminates theconnection with the second communication terminal device upon notreceiving the response information.
 7. The communication systemaccording to claim 1, wherein the communication device has aconfiguration in which an access point device having the wireless LANaccess point function and a display device having the display functionconnect to each other via communication, the first communicationterminal device connects to the access point device via the wirelessLAN, the second communication terminal device connects, under permissionfrom the first communication terminal device, with the access pointdevice via the wireless LAN and uses the display function of the displaydevice via the access point device through the connection via thewireless LAN, the first communication terminal device and the accesspoint device communicate with each other to confirm whether to continueor terminate the permission, and, in response to a termination of thepermission, the access point device terminates the connection with thesecond communication terminal device via the wireless LAN to make thesecond communication terminal device unable to use the display function.8. The communication system according to claim 1, wherein, for thepermission, the first communication terminal device transmits, to thesecond communication terminal device, connection information necessaryfor a connection via the wireless LAN through short range communicationwith the second communication terminal device, and the secondcommunication terminal device transmits address information on thesecond communication terminal device to the first communication terminaldevice, the first communication terminal device transmits the addressinformation on the second communication terminal device to thecommunication device, the communication device registers the addressinformation on the second communication terminal device into apermission list, the second communication terminal device connects tothe communication device via the wireless LAN by using the connectioninformation, upon the permission being to be terminated, the firstcommunication terminal device causes the communication device to deletethe address information on the second communication terminal device fromthe permission list of the communication device, and, upon the addressinformation on the second communication terminal device being notregistered in the permission list, the communication device terminatesthe connection with the second communication terminal device.
 9. Thecommunication system according to claim 1, wherein, for the permission,the first communication terminal device transmits, to the secondcommunication terminal device, connection information necessary for aconnection via the wireless LAN through short range communication withthe second communication terminal device, and the second communicationterminal device transmits address information on the secondcommunication terminal device to the first communication terminaldevice, the first communication terminal device registers the addressinformation on the second communication terminal device into apermission list, the second communication terminal device connects tothe communication device via the wireless LAN by using the connectioninformation, upon the permission being to be terminated, the firstcommunication terminal device deletes the address information on thesecond communication terminal device from the permission list, and thecommunication device performs communication for confirmation with thefirst communication terminal device and, upon the address information onthe second communication terminal device being not registered in thepermission list of the communication device, terminates the connectionwith the second communication terminal device.
 10. The communicationsystem according to claim 1, wherein, for the permission, the firstcommunication terminal device requests a one-time password from thecommunication device, and the communication device responds with theone-time password, the first communication terminal device transmits, tothe second communication terminal device, connection informationincluding the one-time password necessary for a connection via thewireless LAN through short range communication with the secondcommunication terminal device, and the second communication terminaldevice connects to the communication device via the wireless LAN byusing the connection information including the one-time password. 11.The communication system according to claim 1, wherein, for thepermission, the second communication terminal device performs shortrange communication with the communication device, the communicationdevice transmits, to the second communication terminal device,connection information necessary for a connection via the wireless LAN,and the second communication terminal device transmits addressinformation on the second communication terminal device to thecommunication device, the communication device registers the addressinformation on the second communication terminal device into apermission list, the second communication terminal device connects tothe communication device via the wireless LAN by using the connectioninformation, upon the permission being to be terminated, the firstcommunication terminal device causes the communication device to deletethe address information on the second communication terminal device fromthe permission list of the communication device, and, upon the addressinformation on the second communication terminal device being notregistered in the permission list, the communication device terminatesthe connection with the second communication terminal device.
 12. Thecommunication system according to claim 1, wherein, for the permission,the second communication terminal device requests a one-time passwordfrom the communication device through short range communication with thecommunication device, and the communication device transmits connectioninformation including the one-time password necessary for a connectionvia the wireless LAN, to the second communication terminal device, andthe second communication terminal device connects to the communicationdevice via the wireless LAN by using the connection informationincluding the one-time password.
 13. The communication system accordingto claim 1, wherein, for the permission, the first communicationterminal device transmits, to the second communication terminal device,connection information necessary for a connection via the wireless LANthrough short range communication with the second communication terminaldevice, the second communication terminal device connects to thecommunication device via the wireless LAN by using the connectioninformation, after the communication device and the second communicationterminal device connect to each other, the communication device or thefirst communication terminal device performs communication forconfirming whether to continue or terminate the permission, andcontinues the connection between the communication device and the secondcommunication terminal device upon the permission being to be continued,while terminating the connection between the communication device andthe second communication terminal device upon the permission being to beterminated, and, in the short range communication, the firstcommunication terminal device displays a bar code representing theconnection information on a display screen thereof and the secondcommunication terminal device captures an image of the bar code with acamera to read the connection information.
 14. A communication devicefor constituting a communication system including a first communicationterminal device having a wireless LAN connection function; a secondcommunication terminal device having a wireless LAN connection function;and the communication device having a wireless LAN access point functionand a display function, the first communication terminal deviceconnecting to the communication device via a wireless LAN, the secondcommunication terminal device connecting, under permission from thefirst communication terminal device, to the communication device via thewireless LAN and using the display function of the communication devicethrough the connection, the first communication terminal device and thecommunication device communicating with each other to confirm whetherthe permission for the second communication terminal device to connectto and use the communication device is to be continued or terminated,and, in response to a termination of the permission, the communicationdevice terminating the connection with the second communication terminaldevice via the wireless LAN to make the second communication terminaldevice unable to use the display function.
 15. A communication terminaldevice for constituting a communication system including a firstcommunication terminal device having a wireless LAN connection function;a second communication terminal device having a wireless LAN connectionfunction; and a communication device having a wireless LAN access pointfunction and a display function, the communication terminal deviceserving as the first communication terminal device, the firstcommunication terminal device connecting to the communication device viaa wireless LAN, the second communication terminal device connecting,under permission from the first communication terminal device, to thecommunication device via the wireless LAN and using the display functionof the communication device through the connection, the firstcommunication terminal device and the communication device communicatingwith each other to confirm whether the permission for the secondcommunication terminal device to connect to and use the communicationdevice is to be continued or terminated, and, in response to atermination of the permission, the communication device terminating theconnection with the second communication terminal device via thewireless LAN to make the second communication terminal device unable touse the display function.